Temperature control for oil filled bushings



TEMPERATURE CONTROL FOR OIL FILLED BUSHINGS Filed June 23, 1954 IIWENTOR W////0m A. lfillebrand ATTORNEY Patented Dec. 4, 1934 UNITED STATES PATENT OFFICE William A. Hillebrand, Berkeley, Calii., assignor to The Ohio Brass Company, Mansfield, Ohio, a corporation of New Jersey Application June 23, 1934, Serial No. 732,183

3Claims.

invention relates to electrical devices which contain an insulating liquid and especially devices such as bushing insulators which may have-capacitance couplers associated therewith. Although I have shown the invention as applied to a-bushing insulator, it will be understood that itisapplicable to other forms of electrical appatrol the temperature within the housing.

A further object of the invention is to provide a. device of the class named which shall be of improved construction and operation,

1 Another object of the invention is to provide mea'ns for readily testing the oil in the bushing and illtering if necessary without disconnecting the bushing.

. Other objects and advantages will appear from the following description.

The invention is exemplified by the combinatipn and arrangement of parts shown in the accompanying drawing and described in the following specification, and it is more particularly pointed out in the appended claims.

In the drawing:

I Fig. 1 is a somewhat diagrammatic elevation with parts in section showing the application of the present invention to a bushing insulator.

vFig, 2 is a section on line 2-2 oi Fig. 1.

In the drawing the numeral designates an insulator bushing having internal baiiles 11, 12 and 13 and a central conductor 14. The battle 11 is supported from the central flange 9 which supports the bushing insulator, and the baffles 12 and 13 may be supported in any suitable manner as by means of the central conductor 14. The bushing is normally filled with an insulating liquid, such as oil, and is provided with connecting pipes 15 and 16. The pipe 15 is provided with branches 1'1 which enter through the outer shell 10 and into the space 18 between the shell 10 and the baifle 11 above the central flange 9. The pipe 16 is provided with branches 19 which enter the space 20 between the baflles 10 and 11 below the flange 9. The flange 9 separates the spaces 18 and 20 but these spaces are open into the interior of the bushing at their upper and lower ends respectively. Free communication is provided between the-spacessurmunding the internal baflles 12 and 13 and the upper and lower ends of the bushing. 00 The baflle 12 is provided with a metallized surface 21 which forms an electrostatic coupling with the conductor 14 and a lead 22 is connected with the surface 21 and extends outside of the bushing for attachment with any device to be energized by 66 the charging current from the coupling 21. The pipe 15 communicates with a chamber 23 in which are located a'number oi thermostats 24, 25 and 26. A pipe 27 connects the chamber 23 with a circulating pump 28 which is connected with a 70 radiator 29 having a pipe 30 extending back through a heating chamber 31 to the pipe 16. A fan 32 is provided for creating a current of air over the surface of the radiator 29' to facilitate cooling of the liquid circulated through the radi- 76 ator. A spray system 33 is also provided for further cooling the radiator when necessary. The spray system 33 is provided with'a pipe 34 controlled by avalve 35. The valve 35 is normally held closed by a spring 36 but is arranged to be open by means of a solenoid 3'7.

The radiator 29 is provided with a by-pass 38 having a valve 39 therein normally held in its closed position by a spring 40 but arranged to be open by a solenoid 41. The pipe 30 has a valve 42 normally held open by a spring 43 and arranged to be closed by a solenoid 44. The pump 28 and fan 32 are driven by a motor 45 supplied with current from a suitable source 46 which is controlled by a relay 4'7. The chamber 31 contains a heating coil 48 supplied with current from a source 49 controlled by a; relay 50. The relay 50 is, in turn, controlled by a relay 51 connected to the source 49 by leads 52 and 53. The lead 53 passes through a relay 54 which controls the current in the solenoid 44 and also through a relay 55 which controls the current in the solenoid 41 and also through the relay 47 which controls the current in the motor 45. Current is supplied to the solenoids 41, and 44 from the source 49 through conductors 56. The relay 47 may also be supplied with current from the source 46 through a conductor 57, thermostat 25, and leads 58 and 59. The solenoid 37 for the valve 35 is supplied with current from the source 46 through leads 60 which are controlled by a relay 61. The relay 61 is supplied with current from the source 46 through leads 62 and 63 controlled by the thermostat 24.

The operation or the device is as follows: When 1 the temperature of the ofl in the circulating system for the bushing is at a proper working value,

,' of the oil rises above normal operating temperature, the thermostat 25 will first close, which completes the circuit through the leads 57, 58 and 59 and the relay 47. This closes the motor switch and starts the motor 45. This will cause oil to circulate through the pipe 15, radiator 29, valve 42, pipe 30, chamber 31 and pipe 16. Since the openings of the two pipes into the bushing are separated by the flange 9, the oil entering through the pipe 19 will first pass downwardly through the space 20, through the lower end of the bushing and then up through the central portion of the bushing to the top end thereof and back down through the space 18 to the branches 17, and will be returned through the pipe 15 and head 33 to be applied to the radiator 29 and thus further cool the oil in the system. If the temperature now is reduced to its normal point, the thermostats 24 and 25 will again open in the reverse order in which they closed so as to maintain the desired temperature.

If at any time the temperature falls below the normal value, the thermostat 26 will be closed, completing the circuit through the relays 51, 47, 55 and 54. The relay 47 will start the motor so as to operate the pump 28 and again circulate the oil through the bushing. The relay 55, however. will now complete the circuit through the solenoid 41 and openthe by-pass 38 so that the circulating oil will pass by the radiator 29. The relay 54 will also be operated to close the valve 42 so that the oil will not pass through the radiator. The relay- 51 will close the circuit through the relay 50 which, in turn, will close the circuit through the heating coil 48- and heat the oil as it passes through the chamber 31. In this way the oil is automatically heated whenever the temperature falls-below a normal point. It will be understood of course that any number of steps may be provided in the heating mechanism controlled by suitable relays so as to maintain the desired temperature, but usually a single heating coil will be suflicient as the current will be cut ofi from the coil when the temperature reaches the desired point and will be restored if the temperature again drops below that point.

Temperature control of the bushing or other apparatus is especially desirable where it is used for electrostatic coupling because the electrostatic capacitance of the dielectric members varies with the temperature and it is desirable to maintain a constant capacitance in order that the amount of current supplied by the capacitance coupling will not be changed by variations in temperature. This is especially true where the current is used for metering and should be an accurate indication of the voltage between the main conductor and ground.

The fact that the oil circulates through the bottom portion of the bushing prevents the accumulation at this point of oil that contains water or other contaminating material, and the further fact that this oil is carried to a point outside of the bushing makes it possible to test the oil at any time and filter it if necessary. Means may. be provided for circulating the oil through a suitable filter before it returns. to the bushing and valves provided to divert the oil through this filter. By this means, whenever the oil is found to be contaminated, it may be circulated through the filter until it is again properly cleaned. Such a filter is indicated at to which the oil may be diverted from the pipe 30 by suitable valves 66.

I claim: Y 4

1. The combination with a housing member having an insulating liquid therein, a capacitance device contained in said housing member, force feeding mechanism for circulating the liquid in said housing, and means for controlling the temperature of the circulating liquid.

'2. The combination with a conductor and a capacitance coupling for diverting energy from said conductor comprising an element of conducting material and a dielectric interposed between said element of conducting material and said conductor, of means for regulating the temperature of said dielectric for controlling the capacitance of said coupling, said regulating means comprising an insulating fluid in which said dielectric is submerged, a circulating system for said fluid, means for heating said fluid when the temperature thereof falls below a predetermined value, and means for cooling said fiuid when said temperature rises above a certain value.

3. The combination with a conductor, of means for diverting energy from said conductor, said means comprising an insulator having a chamber therein through which said conductor extends,

an element of conducting material disposed'within said chamber, a dielectric interposed between said conductor and said element of conducting material, an insulating fluid in which said .dielectric is submerged, a circulating system for said fluid, means for heating the fluid in said system, means for cooling the fluid in said system, and thermally controlled means for bringing-said heating and cooling means into operation respectively when the temperature of said fluid is outside of a predetermined range. v

WILLIAM A. HILLEBRAND. 

